This invention relates to a vehicle seat assembly with a resetting device.
It is known to provide resetting devices in vehicle seat assemblies, in order to facilitate resetting of a first seat component which has been adjusted relative to a second seat component. On a vehicle seat a backrest for example is pivotable relative to a lower seat part and in particular foldable forwards into a so-called cargo position folded forwards. Folding back of the backrest here is supported by a usually mechanical resetting device with at least one spring element. In this way, a user must apply less force, in order to fold the backrest back. The corresponding spring element is tensioned when the backrest is pivoted, so that the energy stored thereby as resetting force supports folding back of the backrest when the spring element is relaxed again. Backrests of motor vehicles from the middle upper class usually also have a mechanical resetting device to support the adjustment of the backrest out of the cargo position, in order to improve the comfort, provide for a single-handed operation and/or facilitate putting up of the backrest.
Comparable resetting devices furthermore are also known to support setting back during height adjustments or longitudinal adjustments of vehicle seats. For example, in so-called easy-entry mechanisms in which an entry is facilitated for a rear passenger by forward folding of the backrest and simultaneous longitudinal displacement of the seat substructure, folding back of the backrest relative to the seat substructure likewise will be supported by a resetting device with a spring element, just like pushing back of the seat substructure relative to a floor assembly of the vehicle seat.
Furthermore, in particular in vehicle seats with detent fittings a spring support is necessary for the forward adjustment of the backrest, as otherwise the backrest might stop or even fall backwards when the detent fitting is released.
From DE 198 10 471 C1 it is known for example to provide a resetting means with a spring element in a motor vehicle seat with an electrically inclination-adjustable backrest, which spring element acts directly both on a seat substructure and on a backrest of the vehicle seat. Depending on the inclination of the backrest, a line of action of the spring element will extend above or below a horizontal axis. In DE 198 10 471 C1 the spring element preferably is formed as extendable coil spring and each articulated directly to the seat substructure and the backrest. It is not disclosed how the resetting device equipped with the spring element can be designed in detail. In particular, it is not disclosed how the articulation of the spring element to the backrest can be realized.
From US 2005/0269451 A1 there is furthermore known a vehicle seat for an aircraft, in which a resetting device with gas pressure springs is provided as resetting means, in order to support resetting of a backrest folded backwards and resetting of a seat cushion of the seat substructure inclined upwards. The gas pressure springs here are coupled with at least one force transmission element in the form of a rocker arm, in order to for example convert a swivel movement of the backrest into a translatory adjusting movement of a piston of a gas pressure spring and thereby provide a resetting force, when the backrest is pivoted with respect to a neutral position in which the backrest is put up. A longitudinal axis of the respective gas pressure spring and hence an adjustment axis of the longitudinally shiftable piston always extends vertically to the pivot axis of the backrest or the seat substructure. The arrangement and accommodation of the corresponding resetting device hence has little variability and also is comparatively expensive and bulky due to the necessary provision of a linkage with at least one rocker arm as force transmission element.
DE 10 2007 027 655 A1 discloses a vehicle seat in which a resetting device with a spring element is provided, in order to pretension a pivotable backrest relative to a seat substructure on the one hand into a comfort position referred to as first position of use, when the backrest is folded forwards in direction of the seat substructure into a cargo position referred to as second position of use, and on the other hand pretension the same in direction of the cargo position, when the backrest is in a comfort position. For this purpose, the resetting device includes a spring element which is fixed at the seat substructure and which is engaged by a flexible traction means in the form of a traction cable. One end of the traction cable engages the spring element, while the other end of the traction cable is connected with the pivotable backrest. To selectively deflect the traction cable in direction of the backrest, a deflection pulley firmly mounted on the seat substructure is provided. On this deflection pulley the traction cable is deflected by less than 90°, in order to exert a torque resetting the backrest in direction of the other, second or first position of use via the spring element acting directly on the traction cable in each first or second position of use of the backrest.
The resetting device known from DE 10 2007 027 655 A1 is of comparatively simple construction. In practice, however, a sufficiently safely adjustable and compact resetting device hardly can be realized by the same, as the traction cable must act directly on the spring element in the form of a coil spring subjected to a tensile stress. This also involves the fact that the traction cable possibly must be installed at the vehicle seat with great expenditure.
From WO 2011/086 165 A1 A there is furthermore known a vehicle seat in which a spring element pretensioned in a position of use of the backrest is provided, in order to fold the backrest forwards with power assistance on release of a backrest lock. The spring element is rotatably attached to a backrest rear wall of the backrest. A stationary stop, relative to which the backrest can be pivoted, cooperates with the spring element, so that in the position of use of the backrest, in which a seat user can sit down on the vehicle seat and his back is supported by the backrest, the spring element is pretensioned and exerts a resetting force on the backrest into a cargo position folded forwards.
The spring element of WO 2011/086165 A1, which is designed as torsion bar spring or torsion spring, allows a space-saving accommodation of the spring element at the vehicle seat. However, the solution described here merely is suitable for pretensioning the backrest into a cargo position, but not for supporting a resetting movement of the backrest from the cargo position into a position of use. In addition, this known solution is not suited to support the inclination adjustment of the backrest relative to the seat substructure. The arrangement of the spring element described in WO 2011/086165 A1 also tends to introduce combined bending and torsional forces into the spring element, which likewise have a negative effect on the useful life.